Effects of Lanthanum on Bone Resorbing Activity of Rabbit Mature Osteoclasts Co-Cultured with Osteoblasts

The effects of lanthanum (Ⅲ) on the bone resorbing activity of rabbit mature osteoclasts (OCs) in the presence of osteoblasts (OBs) were studied in vitro by measuring the number and area of absorption pits. La(Ⅲ) at concentrations ranging from 1.00×10-5 to 1.00×10-8 mol·L-1 show no effect on mature OC number (P＞0.05). In the OC-OB co-culture systems without La(Ⅲ), osteoblasts alone did not influence the pit number and area whether the two kinds of cells were in contact or not (P＞0.05). Under the OC-OB not-in-contact condition, the effect of La(Ⅲ) on the bone-resorbing activity of OCs was similar to that of La(Ⅲ) in the absence of OBs (P＞0.05). However, while OCs were in direct contact with OBs, the inhibitory effects of La(Ⅲ) on OCs' bone-resorbing activity decreased at the concentrations of 1.00×10-5, 1.00×10-6 and 1.00×10-7 mol·L-1, and the promotion effects increased at 1.00×10-8 mol·L-1 (P＜0.05). The results suggest that direct cell-cell contact between OC and OB be essential for OBs to play their role in regulating the response of OCs to La(Ⅲ).     

Effects of Lanthanum on Formation and Bone-Resorbing Activity of Osteoclast-Like Cells

The effect of La3 on formation of osteoclast-like cells in rabbit bone marrow cells induced by 1,25-dihydroxyvitamin D3 and their bone-resorbing activity was evaluated by counting the number of tartrate resistant-acid phosphatase-positive ［TRAP( )］ multi-nucleated cells and measuring the number and surface area of bone resorption pits with photomicrography and image analysis. The formation and morphological characteristics of osteoclast-like cells and bone resorption pits were observed under a phase contrast inverted microscope. La3 promotes the formation of osteoclast-like cells at the concentration of 1.00×10-8mol·L-1 compared with the control group(P<0.01), whereas no significant change in cell number is observed at higher concentrations(1.00×10-5, 1.00×10-6 and 1.00×10-7 mol·L-1)(P>0.05). La3 at the concentration of 1.00×10-8mol·L-1 also increases the number and surface area of the resorption pits(P<0.01), but inhibits the bone-resorbing activity dose-dependently(P<0.01)at higher concentrations(1.00×10-5, 1.00×10-6 and 1.00×10-7 mol·L-1). These findings suggest that La3 may promote or inhibit the formation and bone-resorbing activity of osteoclast-like cells depending on its concentration.     

Effect of Lanthanum（ Ⅲ ） on Cytosolic Free Calcium in Isolated Rabbit Mature Osteoclasts

Theformationandresorptionofboneismain tainedbytheinteractionsofosteoblasts(OBs)withos teoclasts(OCs),andafunctionalimbalancebetween themmaycausethelossofbonemass.OCsaremulti nucleatedcellsformedbythefusionofmononuclear progenitorsofthemonocyte macrophagef…     

Effects of Ce3＋ , Nd3＋ , Gd3＋, Tb3＋ and Lu3＋ ions on Formation of CaCO3

The effects of lanthanides at various concentrations on CaCO3 crystal growth were studied by X-ray diffraction (XRD), infrared spectra (IR), X-ray photoelectric energy spectra (XPS) and inductively coupled plasma mtms spectrometry (ICP-MS). It was found that the calcite, a stable form of CaCO3 in thermodynamics, is the predominant species. The research indicates that lanthanide ions (Ln3 ) can partly substitute the Ca2 in the lattice of CaCO3 crystals, and change the crystal characterization and direct the ordinal growth of CaCO3 crystals.